1. Field of the Invention
The present invention relates to a probing equipment and a probing method, and particularly, to a probing equipment and a method thereof suitable for simultaneously testing a plurality of chips.
2. Description of the Related Art
In recent days, the diameter of a wafer has been enlarged to allow a greater yield of chip per wafer. Further, the memory capacitance of a semiconductor memory device, e.g. a DRAM or an EEPROM, has been exclusively increased, and accordingly, a time required for testing a chip has become longer.
In the situation as stated above, a multi-probing method of measuring a plurality of chips in one test has been introduced, in order to shorten the processing time.
The above multi-probing method uses a plurality of probe groups provided in a probe card so that a plurality of chips can be tested and processed.
The multi-probing method stated above is disclosed in Jpn. Pat. Appln. KOKAI Publication No. 55-130137.
However, the number of external terminals used in a semiconductor chip tends to increase as the function of a semiconductor has been complicated. The number of probes equipped on one probe card has almost been close to a maximum value. Therefore, it is difficult to expect a much more improved processing ability from the multi-probing method.
As a result, a multi-test-station method has nearly been practiced in which a plurality of test stations are equipped to improve the processing ability, in contrast to the multi-probing method which uses only one test station.
A test station consists of a wafer chuck for chucking a wafer and a retaining portion for retaining a probe card. If a plurality of test stations are connected to a main body of a test equipment, a plurality of wafers can be processed at once. In this multi-test-station method, the number of chips which can simultaneously be subjected to measurement can be increased since the number of test stations can be increased.
The multi-test-station method is disclosed in "THE ECONOMICS OF THE MEMORY TESTER DECISION", 1981 INTERNATIONAL TEST CONFERENCE, p348, p349, and p366.
However, since a plurality of test stations are used, the entire equipment is expensive and the price is not so reasonable in view of the processing ability.
As has been explained above, improvements in the processing ability cannot be expected from a probing equipment using the multi-probing method.
Although a probing equipment using the multi-test-station method attains an improved processing ability, it is expensive and the price is not suitable in view of the processing ability.